Conventional planning tends to consider traffic congestion a significant cost and roadway expansion the preferred solution. It evaluates transport system performance based on indicators such as roadway Level of Service (LOS) and peak-period traffic speeds, and dedicates most transportation resources (road space and money) to roads and parking facilities. This results in predict and provide planning in which roadways are expanded to accommodate anticipated traffic, which creates a self-fulfilling prophecy by inducing additional vehicle use.
Planning decisions often have significant indirect effects. As planners, our challenge is to clearly describe these impacts and quantify them as much as possible so they can be incorporated into decision making. An example of this is the effect that transportation planning decisions have on human health. These impacts are significant but often overlooked or undervalued in the planning process. I have worked on several research projects that explore the nexus between transport planning decisions and public health, and are developing practical tools for incorporating them into planning. Let me share some of my current thinking about this issue.
The newest Texas Transportation Institute Urban Mobility Report was recently released, stimulating discussion of congestion costs and potential solutions. Here are some things you should know when evaluating these issues.